At least, we think it's the most obscure. If there are any more half-references left in Battlefield better obfuscated than this, then we'd better have them declared dead now and accept the fact that we will never find them.
This is a still from Battlefield 3's second campaign mission, Operation Swordbreaker:
On the table you'll see an IED that you're tasked with disarming. Nothing out of the ordinary there. But beyond that, partially covered by shadow, is a circuit board:
And what does Redditor vtsteve do when he finds a circuit board? I'll let him tell you that.
"I have this thing I do, when I see a circuit board texture in a game I try to ID it," said vtsteve. "I know it's strange…"
As it turns out, this particular mainboard is that of Super Contra's '88 coin-op arcade machine.
So there you have it: the most unlikely Contra reference ever conceived, with Konami serial sticker attached. Not exactly Scott Pilgrim, is it?
Last month, an actual egg was uncovered in Armored Kill.
Thanks, StickTwiddlers.